﻿//
// Options.cs
//
// Authors:
//  Jonathan Pryor <jpryor@novell.com>
//  Federico Di Gregorio <fog@initd.org>
//  Rolf Bjarne Kvinge <rolf@xamarin.com>
//
// Copyright (C) 2008 Novell (http://www.novell.com)
// Copyright (C) 2009 Federico Di Gregorio.
// Copyright (C) 2012 Xamarin Inc (http://www.xamarin.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

// Compile With:
//   gmcs -debug+ -r:System.Core Options.cs -o:NDesk.Options.dll
//   gmcs -debug+ -d:LINQ -r:System.Core Options.cs -o:NDesk.Options.dll
//
// The LINQ version just changes the implementation of
// OptionSet.Parse(IEnumerable<string>), and confers no semantic changes.

//
// A Getopt::Long-inspired option parsing library for C#.
//
// NDesk.Options.OptionSet is built upon a key/value table, where the
// key is a option format string and the value is a delegate that is 
// invoked when the format string is matched.
//
// Option format strings:
//  Regex-like BNF Grammar: 
//    name: .+
//    type: [=:]
//    sep: ( [^{}]+ | '{' .+ '}' )?
//    aliases: ( name type sep ) ( '|' name type sep )*
// 
// Each '|'-delimited name is an alias for the associated action.  If the
// format string ends in a '=', it has a required value.  If the format
// string ends in a ':', it has an optional value.  If neither '=' or ':'
// is present, no value is supported.  `=' or `:' need only be defined on one
// alias, but if they are provided on more than one they must be consistent.
//
// Each alias portion may also end with a "key/value separator", which is used
// to split option values if the option accepts > 1 value.  If not specified,
// it defaults to '=' and ':'.  If specified, it can be any character except
// '{' and '}' OR the *string* between '{' and '}'.  If no separator should be
// used (i.e. the separate values should be distinct arguments), then "{}"
// should be used as the separator.
//
// Options are extracted either from the current option by looking for
// the option name followed by an '=' or ':', or is taken from the
// following option IFF:
//  - The current option does not contain a '=' or a ':'
//  - The current option requires a value (i.e. not a Option type of ':')
//
// The `name' used in the option format string does NOT include any leading
// option indicator, such as '-', '--', or '/'.  All three of these are
// permitted/required on any named option.
//
// Option bundling is permitted so long as:
//   - '-' is used to start the option group
//   - all of the bundled options are a single character
//   - at most one of the bundled options accepts a value, and the value
//     provided starts from the next character to the end of the string.
//
// This allows specifying '-a -b -c' as '-abc', and specifying '-D name=value'
// as '-Dname=value'.
//
// Option processing is disabled by specifying "--".  All options after "--"
// are returned by OptionSet.Parse() unchanged and unprocessed.
//
// Unprocessed options are returned from OptionSet.Parse().
//
// Examples:
//  int verbose = 0;
//  OptionSet p = new OptionSet ()
//    .Add ("v", v => ++verbose)
//    .Add ("name=|value=", v => Console.WriteLine (v));
//  p.Parse (new string[]{"-v", "--v", "/v", "-name=A", "/name", "B", "extra"});
//
// The above would parse the argument string array, and would invoke the
// lambda expression three times, setting `verbose' to 3 when complete.  
// It would also print out "A" and "B" to standard output.
// The returned array would contain the string "extra".
//
// C# 3.0 collection initializers are supported and encouraged:
//  var p = new OptionSet () {
//    { "h|?|help", v => ShowHelp () },
//  };
//
// System.ComponentModel.TypeConverter is also supported, allowing the use of
// custom data types in the callback type; TypeConverter.ConvertFromString()
// is used to convert the value option to an instance of the specified
// type:
//
//  var p = new OptionSet () {
//    { "foo=", (Foo f) => Console.WriteLine (f.ToString ()) },
//  };
//
// Random other tidbits:
//  - Boolean options (those w/o '=' or ':' in the option format string)
//    are explicitly enabled if they are followed with '+', and explicitly
//    disabled if they are followed with '-':
//      string a = null;
//      var p = new OptionSet () {
//        { "a", s => a = s },
//      };
//      p.Parse (new string[]{"-a"});   // sets v != null
//      p.Parse (new string[]{"-a+"});  // sets v != null
//      p.Parse (new string[]{"-a-"});  // sets v == null
//

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Globalization;
using System.IO;
using System.Runtime.Serialization;
#if PCL
using System.Reflection;
#else
using System.Security.Permissions;
#endif
using System.Text;
using System.Text.RegularExpressions;

#if LINQ
using System.Linq;
#endif

#if TEST
using NDesk.Options;
#endif

#if PCL
using MessageLocalizerConverter = System.Func<string, string>;
#else
using MessageLocalizerConverter = System.Converter<string, string>;
#endif

#if NDESK_OPTIONS
namespace NDesk.Options
#else
namespace Mono.Options
#endif
{
	static class StringCoda
	{

		public static IEnumerable<string> WrappedLines(string self, params int[] widths)
		{
			IEnumerable<int> w = widths;
			return WrappedLines(self, w);
		}

		public static IEnumerable<string> WrappedLines(string self, IEnumerable<int> widths)
		{
			if (widths == null)
				throw new ArgumentNullException("widths");
			return CreateWrappedLinesIterator(self, widths);
		}

		private static IEnumerable<string> CreateWrappedLinesIterator(string self, IEnumerable<int> widths)
		{
			if (string.IsNullOrEmpty(self))
			{
				yield return string.Empty;
				yield break;
			}
			using (IEnumerator<int> ewidths = widths.GetEnumerator())
			{
				bool? hw = null;
				int width = GetNextWidth(ewidths, int.MaxValue, ref hw);
				int start = 0, end;
				do
				{
					end = GetLineEnd(start, width, self);
					char c = self[end - 1];
					if (char.IsWhiteSpace(c))
						--end;
					bool needContinuation = end != self.Length && !IsEolChar(c);
					string continuation = "";
					if (needContinuation)
					{
						--end;
						continuation = "-";
					}
					string line = self.Substring(start, end - start) + continuation;
					yield return line;
					start = end;
					if (char.IsWhiteSpace(c))
						++start;
					width = GetNextWidth(ewidths, width, ref hw);
				} while (start < self.Length);
			}
		}

		private static int GetNextWidth(IEnumerator<int> ewidths, int curWidth, ref bool? eValid)
		{
			if (!eValid.HasValue || (eValid.HasValue && eValid.Value))
			{
				curWidth = (eValid = ewidths.MoveNext()).Value ? ewidths.Current : curWidth;
				// '.' is any character, - is for a continuation
				const string minWidth = ".-";
				if (curWidth < minWidth.Length)
					throw new ArgumentOutOfRangeException("widths",
							string.Format("Element must be >= {0}, was {1}.", minWidth.Length, curWidth));
				return curWidth;
			}
			// no more elements, use the last element.
			return curWidth;
		}

		private static bool IsEolChar(char c)
		{
			return !char.IsLetterOrDigit(c);
		}

		private static int GetLineEnd(int start, int length, string description)
		{
			int end = System.Math.Min(start + length, description.Length);
			int sep = -1;
			for (int i = start; i < end; ++i)
			{
				if (description[i] == '\n')
					return i + 1;
				if (IsEolChar(description[i]))
					sep = i + 1;
			}
			if (sep == -1 || end == description.Length)
				return end;
			return sep;
		}
	}

	public class OptionValueCollection : IList, IList<string>
	{

		List<string> values = new List<string>();
		OptionContext c;

		internal OptionValueCollection(OptionContext c)
		{
			this.c = c;
		}

		#region ICollection
		void ICollection.CopyTo(Array array, int index) { (values as ICollection).CopyTo(array, index); }
		bool ICollection.IsSynchronized { get { return (values as ICollection).IsSynchronized; } }
		object ICollection.SyncRoot { get { return (values as ICollection).SyncRoot; } }
		#endregion

		#region ICollection<T>
		public void Add(string item) { values.Add(item); }
		public void Clear() { values.Clear(); }
		public bool Contains(string item) { return values.Contains(item); }
		public void CopyTo(string[] array, int arrayIndex) { values.CopyTo(array, arrayIndex); }
		public bool Remove(string item) { return values.Remove(item); }
		public int Count { get { return values.Count; } }
		public bool IsReadOnly { get { return false; } }
		#endregion

		#region IEnumerable
		IEnumerator IEnumerable.GetEnumerator() { return values.GetEnumerator(); }
		#endregion

		#region IEnumerable<T>
		public IEnumerator<string> GetEnumerator() { return values.GetEnumerator(); }
		#endregion

		#region IList
		int IList.Add(object value) { return (values as IList).Add(value); }
		bool IList.Contains(object value) { return (values as IList).Contains(value); }
		int IList.IndexOf(object value) { return (values as IList).IndexOf(value); }
		void IList.Insert(int index, object value) { (values as IList).Insert(index, value); }
		void IList.Remove(object value) { (values as IList).Remove(value); }
		void IList.RemoveAt(int index) { (values as IList).RemoveAt(index); }
		bool IList.IsFixedSize { get { return false; } }
		object IList.this[int index] { get { return this[index]; } set { (values as IList)[index] = value; } }
		#endregion

		#region IList<T>
		public int IndexOf(string item) { return values.IndexOf(item); }
		public void Insert(int index, string item) { values.Insert(index, item); }
		public void RemoveAt(int index) { values.RemoveAt(index); }

		private void AssertValid(int index)
		{
			if (c.Option == null)
				throw new InvalidOperationException("OptionContext.Option is null.");
			if (index >= c.Option.MaxValueCount)
				throw new ArgumentOutOfRangeException("index");
			if (c.Option.OptionValueType == OptionValueType.Required &&
					index >= values.Count)
				throw new OptionException(string.Format(
							c.OptionSet.MessageLocalizer("Missing required value for option '{0}'."), c.OptionName),
						c.OptionName);
		}

		public string this[int index]
		{
			get
			{
				AssertValid(index);
				return index >= values.Count ? null : values[index];
			}
			set
			{
				values[index] = value;
			}
		}
		#endregion

		public List<string> ToList()
		{
			return new List<string>(values);
		}

		public string[] ToArray()
		{
			return values.ToArray();
		}

		public override string ToString()
		{
			return string.Join(", ", values.ToArray());
		}
	}

	public class OptionContext
	{
		private Option option;
		private string name;
		private int index;
		private OptionSet set;
		private OptionValueCollection c;

		public OptionContext(OptionSet set)
		{
			this.set = set;
			this.c = new OptionValueCollection(this);
		}

		public Option Option
		{
			get { return option; }
			set { option = value; }
		}

		public string OptionName
		{
			get { return name; }
			set { name = value; }
		}

		public int OptionIndex
		{
			get { return index; }
			set { index = value; }
		}

		public OptionSet OptionSet
		{
			get { return set; }
		}

		public OptionValueCollection OptionValues
		{
			get { return c; }
		}
	}

	public enum OptionValueType
	{
		None,
		Optional,
		Required,
	}

	public abstract class Option
	{
		string prototype, description;
		string[] names;
		OptionValueType type;
		int count;
		string[] separators;
		bool hidden;

		protected Option(string prototype, string description)
			: this(prototype, description, 1, false)
		{
		}

		protected Option(string prototype, string description, int maxValueCount)
			: this(prototype, description, maxValueCount, false)
		{
		}

		protected Option(string prototype, string description, int maxValueCount, bool hidden)
		{
			if (prototype == null)
				throw new ArgumentNullException("prototype");
			if (prototype.Length == 0)
				throw new ArgumentException("Cannot be the empty string.", "prototype");
			if (maxValueCount < 0)
				throw new ArgumentOutOfRangeException("maxValueCount");

			this.prototype = prototype;
			this.description = description;
			this.count = maxValueCount;
			this.names = (this is OptionSet.Category)
				// append GetHashCode() so that "duplicate" categories have distinct
				// names, e.g. adding multiple "" categories should be valid.
				? new[] { prototype + this.GetHashCode() }
				: prototype.Split('|');

			if (this is OptionSet.Category)
				return;

			this.type = ParsePrototype();
			this.hidden = hidden;

			if (this.count == 0 && type != OptionValueType.None)
				throw new ArgumentException(
						"Cannot provide maxValueCount of 0 for OptionValueType.Required or " +
							"OptionValueType.Optional.",
						"maxValueCount");
			if (this.type == OptionValueType.None && maxValueCount > 1)
				throw new ArgumentException(
						string.Format("Cannot provide maxValueCount of {0} for OptionValueType.None.", maxValueCount),
						"maxValueCount");
			if (Array.IndexOf(names, "<>") >= 0 &&
					((names.Length == 1 && this.type != OptionValueType.None) ||
					 (names.Length > 1 && this.MaxValueCount > 1)))
				throw new ArgumentException(
						"The default option handler '<>' cannot require values.",
						"prototype");
		}

		public string Prototype { get { return prototype; } }
		public string Description { get { return description; } }
		public OptionValueType OptionValueType { get { return type; } }
		public int MaxValueCount { get { return count; } }
		public bool Hidden { get { return hidden; } }

		public string[] GetNames()
		{
			return (string[])names.Clone();
		}

		public string[] GetValueSeparators()
		{
			if (separators == null)
				return new string[0];
			return (string[])separators.Clone();
		}

		protected static T Parse<T>(string value, OptionContext c)
		{
			Type tt = typeof(T);
#if PCL
			TypeInfo ti = tt.GetTypeInfo ();
#else
			Type ti = tt;
#endif
			bool nullable =
				ti.IsValueType &&
				ti.IsGenericType &&
				!ti.IsGenericTypeDefinition &&
				ti.GetGenericTypeDefinition() == typeof(Nullable<>);
#if PCL
			Type targetType = nullable ? tt.GenericTypeArguments [0] : tt;
#else
			Type targetType = nullable ? tt.GetGenericArguments()[0] : tt;
#endif
			T t = default(T);
			try
			{
				if (value != null)
				{
#if PCL
					if (targetType.GetTypeInfo ().IsEnum)
						t = (T) Enum.Parse (targetType, value, true);
					else
						t = (T) Convert.ChangeType (value, targetType);
#else
					TypeConverter conv = TypeDescriptor.GetConverter(targetType);
					t = (T)conv.ConvertFromString(value);
#endif
				}
			}
			catch (Exception e)
			{
				throw new OptionException(
						string.Format(
							c.OptionSet.MessageLocalizer("Could not convert string `{0}' to type {1} for option `{2}'."),
							value, targetType.Name, c.OptionName),
						c.OptionName, e);
			}
			return t;
		}

		internal string[] Names { get { return names; } }
		internal string[] ValueSeparators { get { return separators; } }

		static readonly char[] NameTerminator = new char[] { '=', ':' };

		private OptionValueType ParsePrototype()
		{
			char type = '\0';
			List<string> seps = new List<string>();
			for (int i = 0; i < names.Length; ++i)
			{
				string name = names[i];
				if (name.Length == 0)
					throw new ArgumentException("Empty option names are not supported.", "prototype");

				int end = name.IndexOfAny(NameTerminator);
				if (end == -1)
					continue;
				names[i] = name.Substring(0, end);
				if (type == '\0' || type == name[end])
					type = name[end];
				else
					throw new ArgumentException(
							string.Format("Conflicting option types: '{0}' vs. '{1}'.", type, name[end]),
							"prototype");
				AddSeparators(name, end, seps);
			}

			if (type == '\0')
				return OptionValueType.None;

			if (count <= 1 && seps.Count != 0)
				throw new ArgumentException(
						string.Format("Cannot provide key/value separators for Options taking {0} value(s).", count),
						"prototype");
			if (count > 1)
			{
				if (seps.Count == 0)
					this.separators = new string[] { ":", "=" };
				else if (seps.Count == 1 && seps[0].Length == 0)
					this.separators = null;
				else
					this.separators = seps.ToArray();
			}

			return type == '=' ? OptionValueType.Required : OptionValueType.Optional;
		}

		private static void AddSeparators(string name, int end, ICollection<string> seps)
		{
			int start = -1;
			for (int i = end + 1; i < name.Length; ++i)
			{
				switch (name[i])
				{
					case '{':
						if (start != -1)
							throw new ArgumentException(
									string.Format("Ill-formed name/value separator found in \"{0}\".", name),
									"prototype");
						start = i + 1;
						break;
					case '}':
						if (start == -1)
							throw new ArgumentException(
									string.Format("Ill-formed name/value separator found in \"{0}\".", name),
									"prototype");
						seps.Add(name.Substring(start, i - start));
						start = -1;
						break;
					default:
						if (start == -1)
							seps.Add(name[i].ToString());
						break;
				}
			}
			if (start != -1)
				throw new ArgumentException(
						string.Format("Ill-formed name/value separator found in \"{0}\".", name),
						"prototype");
		}

		public void Invoke(OptionContext c)
		{
			OnParseComplete(c);
			c.OptionName = null;
			c.Option = null;
			c.OptionValues.Clear();
		}

		protected abstract void OnParseComplete(OptionContext c);

		public override string ToString()
		{
			return Prototype;
		}
	}

	public abstract class ArgumentSource
	{

		protected ArgumentSource()
		{
		}

		public abstract string[] GetNames();
		public abstract string Description { get; }
		public abstract bool GetArguments(string value, out IEnumerable<string> replacement);

#if !PCL
		public static IEnumerable<string> GetArgumentsFromFile(string file)
		{
			return GetArguments(File.OpenText(file), true);
		}
#endif

		public static IEnumerable<string> GetArguments(TextReader reader)
		{
			return GetArguments(reader, false);
		}

		// Cribbed from mcs/driver.cs:LoadArgs(string)
		static IEnumerable<string> GetArguments(TextReader reader, bool close)
		{
			try
			{
				StringBuilder arg = new StringBuilder();

				string line;
				while ((line = reader.ReadLine()) != null)
				{
					int t = line.Length;

					for (int i = 0; i < t; i++)
					{
						char c = line[i];

						if (c == '"' || c == '\'')
						{
							char end = c;

							for (i++; i < t; i++)
							{
								c = line[i];

								if (c == end)
									break;
								arg.Append(c);
							}
						}
						else if (c == ' ')
						{
							if (arg.Length > 0)
							{
								yield return arg.ToString();
								arg.Length = 0;
							}
						}
						else
							arg.Append(c);
					}
					if (arg.Length > 0)
					{
						yield return arg.ToString();
						arg.Length = 0;
					}
				}
			}
			finally
			{
				if (close)
					reader.Dispose();
			}
		}
	}

#if !PCL
	public class ResponseFileSource : ArgumentSource
	{

		public override string[] GetNames()
		{
			return new string[] { "@file" };
		}

		public override string Description
		{
			get { return "Read response file for more options."; }
		}

		public override bool GetArguments(string value, out IEnumerable<string> replacement)
		{
			if (string.IsNullOrEmpty(value) || !value.StartsWith("@"))
			{
				replacement = null;
				return false;
			}
			replacement = ArgumentSource.GetArgumentsFromFile(value.Substring(1));
			return true;
		}
	}
#endif

#if !PCL
	[Serializable]
#endif
	public class OptionException : Exception
	{
		private string option;

		public OptionException()
		{
		}

		public OptionException(string message, string optionName)
			: base(message)
		{
			this.option = optionName;
		}

		public OptionException(string message, string optionName, Exception innerException)
			: base(message, innerException)
		{
			this.option = optionName;
		}

#if !PCL
		protected OptionException(SerializationInfo info, StreamingContext context)
			: base(info, context)
		{
			this.option = info.GetString("OptionName");
		}
#endif

		public string OptionName
		{
			get { return this.option; }
		}

#if !PCL
#pragma warning disable 618 // SecurityPermissionAttribute is obsolete
		[SecurityPermission(SecurityAction.LinkDemand, SerializationFormatter = true)]
#pragma warning restore 618
		public override void GetObjectData(SerializationInfo info, StreamingContext context)
		{
			base.GetObjectData(info, context);
			info.AddValue("OptionName", option);
		}
#endif
	}

	public delegate void OptionAction<TKey, TValue>(TKey key, TValue value);

	public class OptionSet : KeyedCollection<string, Option>
	{
		public OptionSet()
			: this(delegate (string f) { return f; })
		{
		}

		public OptionSet(MessageLocalizerConverter localizer)
		{
			this.localizer = localizer;
			this.roSources = new ReadOnlyCollection<ArgumentSource>(sources);
		}

		MessageLocalizerConverter localizer;

		public MessageLocalizerConverter MessageLocalizer
		{
			get { return localizer; }
		}

		List<ArgumentSource> sources = new List<ArgumentSource>();
		ReadOnlyCollection<ArgumentSource> roSources;

		public ReadOnlyCollection<ArgumentSource> ArgumentSources
		{
			get { return roSources; }
		}


		protected override string GetKeyForItem(Option item)
		{
			if (item == null)
				throw new ArgumentNullException("option");
			if (item.Names != null && item.Names.Length > 0)
				return item.Names[0];
			// This should never happen, as it's invalid for Option to be
			// constructed w/o any names.
			throw new InvalidOperationException("Option has no names!");
		}

		[Obsolete("Use KeyedCollection.this[string]")]
		protected Option GetOptionForName(string option)
		{
			if (option == null)
				throw new ArgumentNullException("option");
			try
			{
				return base[option];
			}
			catch (KeyNotFoundException)
			{
				return null;
			}
		}

		protected override void InsertItem(int index, Option item)
		{
			base.InsertItem(index, item);
			AddImpl(item);
		}

		protected override void RemoveItem(int index)
		{
			Option p = Items[index];
			base.RemoveItem(index);
			// KeyedCollection.RemoveItem() handles the 0th item
			for (int i = 1; i < p.Names.Length; ++i)
			{
				Dictionary.Remove(p.Names[i]);
			}
		}

		protected override void SetItem(int index, Option item)
		{
			base.SetItem(index, item);
			AddImpl(item);
		}

		private void AddImpl(Option option)
		{
			if (option == null)
				throw new ArgumentNullException("option");
			List<string> added = new List<string>(option.Names.Length);
			try
			{
				// KeyedCollection.InsertItem/SetItem handle the 0th name.
				for (int i = 1; i < option.Names.Length; ++i)
				{
					Dictionary.Add(option.Names[i], option);
					added.Add(option.Names[i]);
				}
			}
			catch (Exception)
			{
				foreach (string name in added)
					Dictionary.Remove(name);
				throw;
			}
		}

		public OptionSet Add(string header)
		{
			if (header == null)
				throw new ArgumentNullException("header");
			Add(new Category(header));
			return this;
		}

		internal sealed class Category : Option
		{

			// Prototype starts with '=' because this is an invalid prototype
			// (see Option.ParsePrototype(), and thus it'll prevent Category
			// instances from being accidentally used as normal options.
			public Category(string description)
				: base("=:Category:= " + description, description)
			{
			}

			protected override void OnParseComplete(OptionContext c)
			{
				throw new NotSupportedException("Category.OnParseComplete should not be invoked.");
			}
		}


		public new OptionSet Add(Option option)
		{
			base.Add(option);
			return this;
		}

		sealed class ActionOption : Option
		{
			Action<OptionValueCollection> action;

			public ActionOption(string prototype, string description, int count, Action<OptionValueCollection> action)
				: this(prototype, description, count, action, false)
			{
			}

			public ActionOption(string prototype, string description, int count, Action<OptionValueCollection> action, bool hidden)
				: base(prototype, description, count, hidden)
			{
				if (action == null)
					throw new ArgumentNullException("action");
				this.action = action;
			}

			protected override void OnParseComplete(OptionContext c)
			{
				action(c.OptionValues);
			}
		}

		public OptionSet Add(string prototype, Action<string> action)
		{
			return Add(prototype, null, action);
		}

		public OptionSet Add(string prototype, string description, Action<string> action)
		{
			return Add(prototype, description, action, false);
		}

		public OptionSet Add(string prototype, string description, Action<string> action, bool hidden)
		{
			if (action == null)
				throw new ArgumentNullException("action");
			Option p = new ActionOption(prototype, description, 1,
					delegate (OptionValueCollection v) { action(v[0]); }, hidden);
			base.Add(p);
			return this;
		}

		public OptionSet Add(string prototype, OptionAction<string, string> action)
		{
			return Add(prototype, null, action);
		}

		public OptionSet Add(string prototype, string description, OptionAction<string, string> action)
		{
			return Add(prototype, description, action, false);
		}

		public OptionSet Add(string prototype, string description, OptionAction<string, string> action, bool hidden)
		{
			if (action == null)
				throw new ArgumentNullException("action");
			Option p = new ActionOption(prototype, description, 2,
					delegate (OptionValueCollection v) { action(v[0], v[1]); }, hidden);
			base.Add(p);
			return this;
		}

		sealed class ActionOption<T> : Option
		{
			Action<T> action;

			public ActionOption(string prototype, string description, Action<T> action)
				: base(prototype, description, 1)
			{
				if (action == null)
					throw new ArgumentNullException("action");
				this.action = action;
			}

			protected override void OnParseComplete(OptionContext c)
			{
				action(Parse<T>(c.OptionValues[0], c));
			}
		}

		sealed class ActionOption<TKey, TValue> : Option
		{
			OptionAction<TKey, TValue> action;

			public ActionOption(string prototype, string description, OptionAction<TKey, TValue> action)
				: base(prototype, description, 2)
			{
				if (action == null)
					throw new ArgumentNullException("action");
				this.action = action;
			}

			protected override void OnParseComplete(OptionContext c)
			{
				action(
						Parse<TKey>(c.OptionValues[0], c),
						Parse<TValue>(c.OptionValues[1], c));
			}
		}

		public OptionSet Add<T>(string prototype, Action<T> action)
		{
			return Add(prototype, null, action);
		}

		public OptionSet Add<T>(string prototype, string description, Action<T> action)
		{
			return Add(new ActionOption<T>(prototype, description, action));
		}

		public OptionSet Add<TKey, TValue>(string prototype, OptionAction<TKey, TValue> action)
		{
			return Add(prototype, null, action);
		}

		public OptionSet Add<TKey, TValue>(string prototype, string description, OptionAction<TKey, TValue> action)
		{
			return Add(new ActionOption<TKey, TValue>(prototype, description, action));
		}

		public OptionSet Add(ArgumentSource source)
		{
			if (source == null)
				throw new ArgumentNullException("source");
			sources.Add(source);
			return this;
		}

		protected virtual OptionContext CreateOptionContext()
		{
			return new OptionContext(this);
		}

		public List<string> Parse(IEnumerable<string> arguments)
		{
			if (arguments == null)
				throw new ArgumentNullException("arguments");
			OptionContext c = CreateOptionContext();
			c.OptionIndex = -1;
			bool process = true;
			List<string> unprocessed = new List<string>();
			Option def = Contains("<>") ? this["<>"] : null;
			ArgumentEnumerator ae = new ArgumentEnumerator(arguments);
			foreach (string argument in ae)
			{
				++c.OptionIndex;
				if (argument == "--")
				{
					process = false;
					continue;
				}
				if (!process)
				{
					Unprocessed(unprocessed, def, c, argument);
					continue;
				}
				if (AddSource(ae, argument))
					continue;
				if (!Parse(argument, c))
					Unprocessed(unprocessed, def, c, argument);
			}
			if (c.Option != null)
				c.Option.Invoke(c);
			return unprocessed;
		}

		class ArgumentEnumerator : IEnumerable<string>
		{
			List<IEnumerator<string>> sources = new List<IEnumerator<string>>();

			public ArgumentEnumerator(IEnumerable<string> arguments)
			{
				sources.Add(arguments.GetEnumerator());
			}

			public void Add(IEnumerable<string> arguments)
			{
				sources.Add(arguments.GetEnumerator());
			}

			public IEnumerator<string> GetEnumerator()
			{
				do
				{
					IEnumerator<string> c = sources[sources.Count - 1];
					if (c.MoveNext())
						yield return c.Current;
					else
					{
						c.Dispose();
						sources.RemoveAt(sources.Count - 1);
					}
				} while (sources.Count > 0);
			}

			IEnumerator IEnumerable.GetEnumerator()
			{
				return GetEnumerator();
			}
		}

		bool AddSource(ArgumentEnumerator ae, string argument)
		{
			foreach (ArgumentSource source in sources)
			{
				IEnumerable<string> replacement;
				if (!source.GetArguments(argument, out replacement))
					continue;
				ae.Add(replacement);
				return true;
			}
			return false;
		}

		private static bool Unprocessed(ICollection<string> extra, Option def, OptionContext c, string argument)
		{
			if (def == null)
			{
				extra.Add(argument);
				return false;
			}
			c.OptionValues.Add(argument);
			c.Option = def;
			c.Option.Invoke(c);
			return false;
		}

		private readonly Regex ValueOption = new Regex(
			@"^(?<flag>--|-|/)(?<name>[^:=]+)((?<sep>[:=])(?<value>.*))?$");

		protected bool GetOptionParts(string argument, out string flag, out string name, out string sep, out string value)
		{
			if (argument == null)
				throw new ArgumentNullException("argument");

			flag = name = sep = value = null;
			Match m = ValueOption.Match(argument);
			if (!m.Success)
			{
				return false;
			}
			flag = m.Groups["flag"].Value;
			name = m.Groups["name"].Value;
			if (m.Groups["sep"].Success && m.Groups["value"].Success)
			{
				sep = m.Groups["sep"].Value;
				value = m.Groups["value"].Value;
			}
			return true;
		}

		protected virtual bool Parse(string argument, OptionContext c)
		{
			if (c.Option != null)
			{
				ParseValue(argument, c);
				return true;
			}

			string f, n, s, v;
			if (!GetOptionParts(argument, out f, out n, out s, out v))
				return false;

			Option p;
			if (Contains(n))
			{
				p = this[n];
				c.OptionName = f + n;
				c.Option = p;
				switch (p.OptionValueType)
				{
					case OptionValueType.None:
						c.OptionValues.Add(n);
						c.Option.Invoke(c);
						break;
					case OptionValueType.Optional:
					case OptionValueType.Required:
						ParseValue(v, c);
						break;
				}
				return true;
			}
			// no match; is it a bool option?
			if (ParseBool(argument, n, c))
				return true;
			// is it a bundled option?
			if (ParseBundledValue(f, string.Concat(n + s + v), c))
				return true;

			return false;
		}

		private void ParseValue(string option, OptionContext c)
		{
			if (option != null)
				foreach (string o in c.Option.ValueSeparators != null
						? option.Split(c.Option.ValueSeparators, c.Option.MaxValueCount - c.OptionValues.Count, StringSplitOptions.None)
						: new string[] { option })
				{
					c.OptionValues.Add(o);
				}
			if (c.OptionValues.Count == c.Option.MaxValueCount ||
					c.Option.OptionValueType == OptionValueType.Optional)
				c.Option.Invoke(c);
			else if (c.OptionValues.Count > c.Option.MaxValueCount)
			{
				throw new OptionException(localizer(string.Format(
								"Error: Found {0} option values when expecting {1}.",
								c.OptionValues.Count, c.Option.MaxValueCount)),
						c.OptionName);
			}
		}

		private bool ParseBool(string option, string n, OptionContext c)
		{
			Option p;
			string rn;
			if (n.Length >= 1 && (n[n.Length - 1] == '+' || n[n.Length - 1] == '-') &&
					Contains((rn = n.Substring(0, n.Length - 1))))
			{
				p = this[rn];
				string v = n[n.Length - 1] == '+' ? option : null;
				c.OptionName = option;
				c.Option = p;
				c.OptionValues.Add(v);
				p.Invoke(c);
				return true;
			}
			return false;
		}

		private bool ParseBundledValue(string f, string n, OptionContext c)
		{
			if (f != "-")
				return false;
			for (int i = 0; i < n.Length; ++i)
			{
				Option p;
				string opt = f + n[i].ToString();
				string rn = n[i].ToString();
				if (!Contains(rn))
				{
					if (i == 0)
						return false;
					throw new OptionException(string.Format(localizer(
									"Cannot use unregistered option '{0}' in bundle '{1}'."), rn, f + n), null);
				}
				p = this[rn];
				switch (p.OptionValueType)
				{
					case OptionValueType.None:
						Invoke(c, opt, n, p);
						break;
					case OptionValueType.Optional:
					case OptionValueType.Required:
						{
							string v = n.Substring(i + 1);
							c.Option = p;
							c.OptionName = opt;
							ParseValue(v.Length != 0 ? v : null, c);
							return true;
						}
					default:
						throw new InvalidOperationException("Unknown OptionValueType: " + p.OptionValueType);
				}
			}
			return true;
		}

		private static void Invoke(OptionContext c, string name, string value, Option option)
		{
			c.OptionName = name;
			c.Option = option;
			c.OptionValues.Add(value);
			option.Invoke(c);
		}

		private const int OptionWidth = 29;
		private const int Description_FirstWidth = 80 - OptionWidth;
		private const int Description_RemWidth = 80 - OptionWidth - 2;

		public void WriteOptionDescriptions(TextWriter o)
		{
			foreach (Option p in this)
			{
				int written = 0;

				if (p.Hidden)
					continue;

				Category c = p as Category;
				if (c != null)
				{
					WriteDescription(o, p.Description, "", 80, 80);
					continue;
				}

				if (!WriteOptionPrototype(o, p, ref written))
					continue;

				if (written < OptionWidth)
					o.Write(new string(' ', OptionWidth - written));
				else
				{
					o.WriteLine();
					o.Write(new string(' ', OptionWidth));
				}

				WriteDescription(o, p.Description, new string(' ', OptionWidth + 2),
						Description_FirstWidth, Description_RemWidth);
			}

			foreach (ArgumentSource s in sources)
			{
				string[] names = s.GetNames();
				if (names == null || names.Length == 0)
					continue;

				int written = 0;

				Write(o, ref written, "  ");
				Write(o, ref written, names[0]);
				for (int i = 1; i < names.Length; ++i)
				{
					Write(o, ref written, ", ");
					Write(o, ref written, names[i]);
				}

				if (written < OptionWidth)
					o.Write(new string(' ', OptionWidth - written));
				else
				{
					o.WriteLine();
					o.Write(new string(' ', OptionWidth));
				}

				WriteDescription(o, s.Description, new string(' ', OptionWidth + 2),
						Description_FirstWidth, Description_RemWidth);
			}
		}

		void WriteDescription(TextWriter o, string value, string prefix, int firstWidth, int remWidth)
		{
			bool indent = false;
			foreach (string line in GetLines(localizer(GetDescription(value)), firstWidth, remWidth))
			{
				if (indent)
					o.Write(prefix);
				o.WriteLine(line);
				indent = true;
			}
		}

		bool WriteOptionPrototype(TextWriter o, Option p, ref int written)
		{
			string[] names = p.Names;

			int i = GetNextOptionIndex(names, 0);
			if (i == names.Length)
				return false;

			if (names[i].Length == 1)
			{
				Write(o, ref written, "  -");
				Write(o, ref written, names[0]);
			}
			else
			{
				Write(o, ref written, "      --");
				Write(o, ref written, names[0]);
			}

			for (i = GetNextOptionIndex(names, i + 1);
					i < names.Length; i = GetNextOptionIndex(names, i + 1))
			{
				Write(o, ref written, ", ");
				Write(o, ref written, names[i].Length == 1 ? "-" : "--");
				Write(o, ref written, names[i]);
			}

			if (p.OptionValueType == OptionValueType.Optional ||
					p.OptionValueType == OptionValueType.Required)
			{
				if (p.OptionValueType == OptionValueType.Optional)
				{
					Write(o, ref written, localizer("["));
				}
				Write(o, ref written, localizer("=" + GetArgumentName(0, p.MaxValueCount, p.Description)));
				string sep = p.ValueSeparators != null && p.ValueSeparators.Length > 0
					? p.ValueSeparators[0]
					: " ";
				for (int c = 1; c < p.MaxValueCount; ++c)
				{
					Write(o, ref written, localizer(sep + GetArgumentName(c, p.MaxValueCount, p.Description)));
				}
				if (p.OptionValueType == OptionValueType.Optional)
				{
					Write(o, ref written, localizer("]"));
				}
			}
			return true;
		}

		static int GetNextOptionIndex(string[] names, int i)
		{
			while (i < names.Length && names[i] == "<>")
			{
				++i;
			}
			return i;
		}

		static void Write(TextWriter o, ref int n, string s)
		{
			n += s.Length;
			o.Write(s);
		}

		private static string GetArgumentName(int index, int maxIndex, string description)
		{
			if (description == null)
				return maxIndex == 1 ? "VALUE" : "VALUE" + (index + 1);
			string[] nameStart;
			if (maxIndex == 1)
				nameStart = new string[] { "{0:", "{" };
			else
				nameStart = new string[] { "{" + index + ":" };
			for (int i = 0; i < nameStart.Length; ++i)
			{
				int start, j = 0;
				do
				{
					start = description.IndexOf(nameStart[i], j);
				} while (start >= 0 && j != 0 ? description[j++ - 1] == '{' : false);
				if (start == -1)
					continue;
				int end = description.IndexOf("}", start);
				if (end == -1)
					continue;
				return description.Substring(start + nameStart[i].Length, end - start - nameStart[i].Length);
			}
			return maxIndex == 1 ? "VALUE" : "VALUE" + (index + 1);
		}

		private static string GetDescription(string description)
		{
			if (description == null)
				return string.Empty;
			StringBuilder sb = new StringBuilder(description.Length);
			int start = -1;
			for (int i = 0; i < description.Length; ++i)
			{
				switch (description[i])
				{
					case '{':
						if (i == start)
						{
							sb.Append('{');
							start = -1;
						}
						else if (start < 0)
							start = i + 1;
						break;
					case '}':
						if (start < 0)
						{
							if ((i + 1) == description.Length || description[i + 1] != '}')
								throw new InvalidOperationException("Invalid option description: " + description);
							++i;
							sb.Append("}");
						}
						else
						{
							sb.Append(description.Substring(start, i - start));
							start = -1;
						}
						break;
					case ':':
						if (start < 0)
							goto default;
						start = i + 1;
						break;
					default:
						if (start < 0)
							sb.Append(description[i]);
						break;
				}
			}
			return sb.ToString();
		}

		private static IEnumerable<string> GetLines(string description, int firstWidth, int remWidth)
		{
			return StringCoda.WrappedLines(description, firstWidth, remWidth);
		}
	}
}
